Keyboard operated printing machine



Dec. 11, 1951 c. CHISHOLM 2,578,286

KEYBOARD OPERATED PRINTING MACHINE Filed Aug 25, 1949 11 Sheets-Sheet 1z 3 4 7 a a n a. s

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I7 TTORNEYJ Dec. 11, 1951 c. CHISHOLM 2,578,285

'. KEYBOARD OPERATED PRINTING MACHINE Filed Aug. 23, 1949 11 Sheets$haet2 60 v m- I 4/ C1. IFroI/C IIISIIOLM HTTORNEYS Dec. 11', 1951 c.CHISHOLM KEYBOARD OPERATED PRINTING MACHINE i1 Sheets-Sheet 4 Filed Aug.23, 1949 INVENTOR. CZ/FTON (HIS/YOU! Dec. 11, 1951 c. CHISHOLM KEYBOARDOPERATED PRINTING MACHINE 11 Sheets-Sheet 5 Filed Au 23, 1949 swam/kw C:ra/v C HIS/101M w @unhflm Dec. 11, 1951 c. CHISHOLM 2,578,286

KEYBOARD OPERATED PRINTING MACHINE Filed Au 23, 1949 11 Sheets-Sheet 6INVEN TOR. C1. IFTON C/l/s/roz M BY 642, @442, vWflM Dec. 11,. 19.51 c.CHISHOLM 2,578,286

KEYBOARD OPERATED PRINTING MACHINE Filed Aug. 23, 1949 l1 Sheets-Sheet 7fie-4 5 Dec. 11, 1951 c. CHISHOLM KEYBOARD OPERATED PRINTING MACHINEFiled Aug. 25, 1949 11 Sheets-Sheet 8 IN VEN TOR. ('1 IF m/v [ms/104M BYala, 71 442, V 77/ Dec. 11, 1951 c. CHISHOLM KEYBOARD OPERATED PRINTINGMACHINE 11 Sheets-Sheet 9 Filed Aug. 25, 1949 INVENTOR. W (Lino/ 0115mmH 176 encr Dec. 11, 1951 c. CHISHOLM 2,578,286

KEYBOARD OPERATED PRINTING MACHINE Filed Aug. 23, 1949 11 Sheets-Sheet10 m5 r m/ 64 M0 A E 15 FIG. 16

IN VEN TOR. 62 /F 704 (Ir/M104 N @4224, QM, vi! a JTIUAWEX! Dec. 11,1951 c. CHISHOLM 2,573,236

KEYBOARD OPERATED PRINTING MACHINE Filed Aug. 23, 1949 11 Shee'rLs-Sheet11- v u v I N VEN TOR. CZ fro/v Ora/7'01. M

reproduced as in an ordinary typewriter.

Patented Dec. 11, 1951 KEYBOARD OPERATED PRINTING MACHINE CliftonChisholm, Cleveland, Ohio, assignor of one-half to Henry C. Osborn,Cleveland, Ohio, and one-fourth to Marie F. Chisholm Application August23, 1949, Serial N 0. 111,871

17 Claims.

This invention relates to an improved keyboard operated printing ortypewriting machine. More specifically the invention relates to theprovision of an improved power operated, keyboard controlled, printingmachine having an improved work sheet carriage and supporting mechanismtherefor, together with an improved mechanism for moving the carriagetoward the printing member to obtain a clear, distinct and justifiedcopy, similar to letter press printing, and from which a master printingmember, such as a planographic printing plate, may be reproduced as, forinstance, by a photographic transfer process. These, therefore, are thegeneral objects of this invention.

My prior Patents Nos. 2,165,223, 2,165,224 and 2,165,225, issued July11, 1939, and my copending application Serial No. 685,107, filed July20, 1946. now Patent No. 2,506,701, dated May 9, 1950, disclose akeyboard machine of the general type with which the present invention isconcerned. In general, such a machine includes a plurality of individualletter keys for causing a copy to be However, a plurality of space keysare also provided. These space keys are arranged to space the words avarying distance from each other as, for instance, by any selectednumber of units from four to eighteen as desired. The letter keyscontrol mechanism which causes impressions to be made from printing typeof varying widths such as are ordinarily used in letter press printing.

, In using a machine of the type with which this invention is concerned,the operator first types a line in the usual manner, using a standardMechanism, which is dependspace key or bar. out upon the differencebetween the length of the typed line and the length of a standard lineindicates to the operator which space key or keys should be used whenretyping the line to produce a justified or standard length line. Thisinformation is typed by the operator at the end of the line andsubsequent lines are typed using the same procedure. To produce thejustified copy, these typed lines are removed from the machine andretyped, using the space keys indicated at the ends of the respectivelines. The lines so retyped will all be of standard length. The retypedcopy is then removed from the machine and utilized in any well knownmanner to form a master printing member or plate. ple, a planographicprinting plate may be produced from the retyped copy by a photographicreproduction process.

One of the objects of the present invention is to provide an, improvedkeyboard controlled For exam- 1 printing mechanism with an improved worksheet carriage and support therefor which will facilitate thereproduction of an exceedingly clear and distinct copy.

Another object of this invention is to provide a keyboard controlledprinting machine having type of difierent widths, with an improvedmechanism for moving the Work sheet into and out of contact withselected type, and to so arrange such mechanism as to facilitate thecontrol of the movement by the operator.

A further object of the invention is to provide a power operated,keyboard controlled printing machine, with an operating mechanism forselectively controlling the movement of the impression members towardeach other.

A further object is to provide a power operated printing machine havinga rotary type carrier with an improved mechanism for moving the worksheet carriage toward the type carrier when a letter key is depressedand which will render such mechanism inefiective when a space key isdepressed without uncoupling the mechanism from the carriage orotherwise interfering with the normal operation of the machine.

Other objects and advantages of the invention will become more apparentfrom the following description, reference being had to the accompanyingdrawings in which there is illustrated apreferred embodiment of theinvention. The essential characteristics of the invention will besummarized in the claims.

In the drawings, Fig. 1 is a plan view of a machine embodying myinvention; Fig. 2 is an enlarged plan view of the left hand side of themachine, the cover and certain other parts being broken away to moreclearly illustrate the internal construction; Fig. 3 is a plan viewsimilar to Fig. 2 but illustrating the right hand side of the machine;Fig. 4 is a rear elevation of the machine; Fig. 5 is a side elevationlooking at the right hand side of Figs. 1 and 3; Fig. 6 is a partiallongitudinal vertical section taken through the paper carriage, typewheel, and their associated parts, the plane of the section beingindicated by the lines 6-'o' on Figs. 1 and 2; Fig. '7 is a sectiona1detail illustrating the key lever mechanism, certain parts being omittedto clarify the operation of the lever, the plane of the section beingindicated by the lines 'l-'l on Fig. 3; Fig. 8 is a sectional detailsimilar to Fig. 7, but illustrating the lever in a different operatingposition; Fig. 9 is a fragmentary vertical section illustrating a singlerevolution clutch and its operating mechanism, the plane of the sectionbeing indicated 7 by the line 9--9 on Fig. 2; Fig. 10 isifa sectionaldetail, on an enlarged scale, illustrating a ratchet mechanism forcontrolling the progress of a paper carriage, the plane of the sectionbeing substantially indicated by the offset line ill-ii on Fig. 2; Fig.11 is a sectional detail illustrating a portion of the linkage foractuating the paper carriage, the Plane of the section being indicatedby the line i ll on Fig. 3; Fig. 12 is a sectional detail similar toFig. 11, but illustrating the parts in a difierent position; Fig. 13 isa sectional detail, the plane of the section being indicated by the lineiii-i3 on Fig. 12; Fig. 14 is a fragmentary elevation of another portionof the linkage shown in Fig. ll, looking at the right hand side of Fig.2; Figs. 15 and 16 are sectional details the planes of the section beingindicated b the corre spondingly numbered lines on Figs. 14 and 15; Fig.17 is a sectional detail, certain parts being broken away, of amechanism for adjusting the paper carriage to control the left handmargin of the imprint, the plane of the section being substantially thesame as that of Fig. 6; Figs. 18, 19 and 20 are sectional details asindicated by the correspondingly numbered lines on Fig. 17; Fig. 21 is asectional detail of a portion of the carriage supporting and guidingmechanism, the plane of the section being indicated by the line 21-2! onFig. 6; and Fig. 22 is an electrical diagram illustrating an electricalcircuit for the machine.

In the drawings, and particularly in Fig. l, the keyboard operatedprinting machine, in connection with which the present invention hasbeen illustrated, comprises a frame [6 which supports the improved paperor work sheet carriage ii. This carriage is progressed across the framefrom rig t to left by a suitable variable feed mechanism, such as thatof my copending application Serial No. 751,303, filed May 29, 1947, nowPatent No. 2,505,702, dated May 9, 1950. The improved carriage,hereinafter to be described in detail, carries a platen mechanism,generally indicated at it, and a work sheet so that the latter may beline spaced. A wheel M is mounted on the frame ill, for rotation as aunit about a vertical axis. This type wheel may carry four annular bandsof type each comprising an entire font. The bands are arranged in pairs,the upper band of each pair carrying lower case type and the lower bandupper case type. One pair of type bands may be 6-po nt type and theother 8-point type. The type wheel is arranged to be selectivelypositioned, relative to the platen mechanism E2, to enable use of thedesired font of type, as for instance, by the mechanism of my copendingapplication Serial No. 752,995, filed June 6, 1947, now Patent No.2,506,704, dated May 9, 1959. A keyboard it controls the rotation of thetype wheel so as to bring the desired type of a selected font intoprinting position. The keyboard 55 also controls the mechanism of thepresent invention which causes the paper carriage l I to move bodilytoward the type wheel hi to cause an impression to be made of theselected character or type.

Following the impression of a character on the work sheet, the papercarriage H is moved from right to left a distance which is determined bythe width of the character last impressed. The total number of spacesbetween the words of a printed line, and the total distance the worksheet is advanced, controls the relative positions of a justifying scalecarried by a drum I? and an indicator or pointer 18. The drum I? andindicator is are mounted at the'right hand side of the machine in frontof the paper carriage and are described in detail in my copendingapplication Serial No. 585,107 heretofore referred to.

To facilitate the operation of the mechanism, a copyholder, generallindicated at [9, is positioned between the keyboard 15 and the typewheel M. This copyholder may comprise coacting rollers one of which isshown in Fig. l at 23, and between which a sheet to be copied is placed.It also may include a suitable copy support or guide 25. The arrangementis such that the operator rotate the roll 23 by means of knobs to bringthe desired line of the copy into position where it is readily visibleby the operator.

In making the initial impression, the operator uses a space bar 23 ofthe keyboard :5 to cause the paper carriage to be advanced for wordspacing. Each time this space bar is actuated it causes the carriage tobe advanced a predetermined distance, which, in the constructionillustrated, is four units. Each time a character key 24 is actuated,the carriage ii is advanced a number of units equivalent to the width ofthe type selected by the actuation of such key.

The keyboard Hi is also provided with a plurality of justifying spacekeys 25 each of which, when actuated, causes the carriage to be advanceda different number of units. In the form illustrated the keys arearranged to advance the carriage any desired number of units from fiveto eighteen inclusive.

The operator, during the initial typing, causes the typed line toapproach the desired length as nearly as possible. At this time theindicator it is opposite indicia, on the justifying scale carried by thedrum ll, which will indicate which spaced key or keys 25, if usedinstead of the space bar 23, in retyping for word spacing, will causethe typed line to be justified or extended to a line equal to the lengthof line desired for the finished copy. This designation is then typed atthe end of the line.

Following the typing of the justification indicia at the end of a typedline the operator depresses a release key 2?. The depression of this keis described in detail in my copending application Serial No. 635,107.The depression of this key causes the paper carriage ii to be returnedto its right hand or starting position, advances the work sheet on thecarriage H to position it to receive thenext line to be printed, andcauses the justifying scale drum i? and indicator 5% to return to theirstarting positions. Thus the machine is made ready for the typing of thenext line.

After all lines of a page have been typed or printed, the initial copyis removed from the carriage I l and placed in the copyholder l9, andthe sheet is then retyped. During this retyping the words are spaced bythe keys 25 designated by the indicia at the end of the respectivelines. The retyped page is thus justified and simulates a letter pressimpression.

The improved work sheet or paper carriage H and the platen mechanism l2are best illustrated in Figs. 1 to G and 17 to 21 both inclusive. Asthere illustrated, the paper carriage ii comprises a pair of end plates36 and 3 spaced apart by cross frame members, such as'bars 32 to 37inclusive and rods 33, all of which are secured at their ends to the endplates. The frame member or bar 3? comprises part or". the platenmechanism 12. This bar is positioned at the front of the carriage and isprovided with a longitudinally ex-- standing frame brackets 55.

tend-ing, forwardly facing groove in which a plastic bar 39 i fixedlyseated. This bar 39 coacts with the type wheel M to make the impressionon.

the work sheet.

' The platen bar 31 extends horizontally in front of the carriage l land is backed up by a platen roll 40. This roll extends horizontallyacross the carriage directly to the rear of the platen bar 31 with tsaxis in the same horizontal plane as the bar. The roll 4!] comprises ametal cylinder which is secured to a shaft 4|, as by pins, one of whichis shown at 42 in Fig. 6. The shaft 4| extends .through and isjournalled in the end plates and 31 of the carriage II, and the endsthereof are provided with knobs 43 by means of which the shaft may bemanually rotated. The periphcry of the platen roll snugly engages therear face of the platen bar 31, which has an arcuate surface 44complementary to the periphery of the roll. The roll 4t reenforces theplaten'bar 3.! throughout its entire length.

Pivotally mounted on a carriage frame rod 45,

above the platen roll 46, are a pair of brackets 48, each of whichcarries a rubber coated roller Similar sets of brackets 48, carryingrollers 43, are mounted on a carriage frame rod which extends below theplaten roll. The brackets 46 and 49 are spring pressed to bring theirrespective rollers 41 and 49 into engagement with the platen roll 40. Awork sheet is passed downward, at the rear of the platen roll 40,between the surface of such roll and a guide plate 59, and extendsforward between the rollers 49 and the roll 45, thence upward around theplaten bars 3'! and 39, and rearward between the platen roll '40 and therollers 41. The guide plate 58 is provided with the usual recesses topermit the 'rolls 49 to engage the sheet.

Mechanism is provided to feed the work sheet upwardly around the platenbars 31 and 39 for line spacing. This is accomplished by rotating theroller 40 either by its knobs 43 or by a suitable ratchet mechanismgenerally indicated at 5|, for instance that illustrated and describedin my copending application Serial No. 685,107, heretofore referred to.However, any of the well known platen roll advancing mechanisms commonlyused on typewriters may be provided for this purpose. Accordingly, adetailed descrip 'tion of such mechanism becomes unnecessary.

The paper carriage H is slidably mounted for movement from right to left(Fig. 1), transversely across "the machine between a pair of up- Asshown in the drawings, particularly in Figs. 1 to 6, the frame it of themachine is provided with a pair of upstanding side brackets which havetheir bases rigidly connected to the frame If) and which are connectedadjacent their upper ends by a comparatively rigid reenforcing bar 56.This bar 56 extends between the brackets in substantially the samehorizontal plane as the platen mechanism l2. Also mounted insubstantially the same horizontal plane as the reenforcing bar 55 andthe platen mechanism [2, are a pair of comparativelt heavy rods 51 and58. The rod '5? is mounted in the frame standards 55 for rotation abouta fixed axis relative thereto but is constrained against axial movement.Each end of the rod 58 is provided with a roller 59 which is slidablymounted in horizontally extending ways 60 formed in the brackets 55.Thus the rod SB-may be reciprocated toward and from the platen! in asubstantially horizontal plane.

The paper carriage is slidably mounted on the rod 58 for movementaxially thereof. Thecarriage end plates 30 and 3| are slidable axiallyalong the rod 58 which is journalled in such plates. Thus the carriagemay move to and from the type wheel l4 as a unit with the bar 58. Thisreciprocation of the carriage is used to effect the printing operationas will hereinafter be described more fully.

The paper carriage is guided in its axial movement along the rod 58 by apair of vertically spaced rollers 65 which coact with opposite faces ofthe carriage frame bar 36. These rollers are best illustrated in Figs. 6and 21. As there shown, a post-like structure 66 is mountedon the frameIE) and extends upward between the carriage end plates to the rear ofthe type wheel 14-. The rollers 65 are journalled on pins 61 carried bythe post 66 and extend forwardly therefrom coacting with the upper andlower surfaces of the carriage frame bar 36. The rollers are ofsufiicient length to permit movement of the carriage toward and from thetype wheel i4 without disengaging the bar 36 which is of a widthsufficient to insure accurate positioning of the carriage [5.

The type wheel [4 is shown in Figs. 1, 2, 3 and 6 as'being drivinglymounted on a vertically extending shaft 10 journalled in a frame bracketH. As heretofore mentioned, each type wheel carries on its periphery twopairs of annular sets orbands of type.' The type in the top band of eachtype pair 14 comprise lower case type, whereas those in the bottom bandof each pair comprise upper case type. The upper pair of bands maycarry, for instance, six point type and the lower pair of bands eightpoint type. I When the machine is in operation the type wheels arecontinuously rotated, the rotation being stopped for the printingoperation under the control of the keyboard I5 as will be hereinaftermore fully described. The type wheels are normits the rotation of theshaft to be stopped for the printing operation without stopping therotation of the drive pulley 12. As such clutches are well known, nodetailed description will be given. Secured to the shaft 13,intermediate its ends, is a gear 16 which meshes with a spiral gear Tldrivingly securedto the type wheel shaft 10 as by a pin I8.

The type wheels l4 are mounted for axial movement on the shaft 10 tobring the upper case band of type of the selected pair into printingposition, that is, in horizontal alignment with the platen l2. Thismovement of the type wheels is controlled from the keyboard l5, andparticularly by a shift key (Figs. 1 and 2). A suitable mechanism forthis purpose is shown and described in my copending application SerialNo, 752,995, filed June 6, 1947. Briefly, the depression of the keyactuates an electric switch 8| (Fig. 22) energizing an electric circuitwhich causes the energization of a solenoid 82 (Figs. 1, 2 and 4). Thissolenoid actuates a lever 83 which raises the type wheel l4 withoutdisturbing its driving connection with its supporting shaft 10. Theweight of the wheel, together with a suitablespring (not shown), returnsthe type wheel to its normal position. Mechanism, which forms no part ofthe present invention but which is shown and described in my copendingapplication 752,995, heretofore referred to, enables the selection ofeither pair of type bands as desired.

The depression of a letter key 24 stops the rotation of the type wheelI4 with the selected type in printing position, while the depression ofthe space bar 23 or a space key 25 stops the type wheel I4 with aportion intermediate two characters in printing position. The mechanismfor accomplishing this is best shown in Figs. 2, 3, 7 and 8. Assh-own,in Fig. '7, each key 24 or 25, as well as the space bar 23, is securedto a respective key lever 85. These levers are pivoted to a stationaryshaft 05.

The key levers 85 are normally held in their uppormost position, againsta stop bar 81 carried by the frame members or posts 84 by individualsprings 88. Each key lever 85 carries a pin 90 which is normally inlatching engagement with a notch 9I formed in the end of respectivelevers 92. The levers 92 are pivoted to a stationary rod 93 extendingacross the frame I0, and are normally retained in the position shown inFig. 'I by individual springs 94 which are interposed between therespective levers 92 and a frame bar 95.

When the operator depresses a key 24 or 25,

or the bar 23, the respective key lever 85 is rocked clockwise againstthe action of its spring 88 to a position where its pin 90 is withdrawnfrom the notch 9! in the respective lever 92. Thereupon a spring 94rocks such lever 92 clockwise about its pivot shaft 93, causing a lug 95on the end of such lever to engage a notch 91 in a disc 98. There are aplurality of such discs one for each lever 92. The discs 98 are keyed tothe main drive shaft 13 so that their notches 91 are spacedcircumferentially one from the other. Thus each disc will stop therotation of the shaft I3, and accordingly the type wheel I4,

in a different circumferential position. Accordingly, any selectedcharacter on the type wheel may be brought into printing positionrelative to the platen mechanism I2;

The depression of a key 23, 24 or 25 also causes the carriage II to movebodily toward the type wheels I4 to cause an impression to be made on awork sheet. As shown in Fig. 8, the rocking of a lever 92, as a resultof the depression of a key, causes such lever to engage a bail I theends of which are pivoted in the bearing members I4 heretoforedescribed. The movement of the bail I00 controls a single revolutionclutch generally indicated at I02 in Figs. 2 and 9. The'driven memberI03 of this clutch is secured to a cam shaft I04 mounted on the frame I0in bearings I05. The driving member I06 of the clutch I02 is rotatablymounted on the shaft I04 and is drivingly connected by gearing with theconstantly rotating drive pulley I2 heretofore described. The singlerotation clutch may be of any well-known make, and hence is notdescribed herein in detail. Suflice it to say that the shaft I04 willrotate consequent upon the withdrawing of a latch I08 from a notch I09in a clutch control member IIO (Fig. 2) whereupon the shaft I04 willmake one complete revolution following which the latch I08 will againengage the-notch I09 and disengage the driving connection.

The'latch I08 .ofthe single revolution clutch 4 02 is the form of. abell crank andis pivoted intermediate its ends as at I I I to a suitableframe bracket. The latch I08 carries a pin II2 engaged by a slot I I3 ina lever I I4 which, as indicated in Fig. 9, is secured to the bail I00.A spring I I5. interposed between the latch I08 and the frame I0, servesto restore the latch I08, the bail I00 and their associated parts totheir normal position as shown in Fig. 9. The action of the spring H5 issuch that it may be readily overcome by the action of any of the springs94 heretofore described.

The movement of the shaft I04 locks the type wheel I4 with the selectedcharacter in printing position prior to the making of an impressiontherefrom. As shown in Fig. 6, a cam H6 is secured to the shaft I04 andis arranged to coact with a roller I I7 carried by one end of a link II8, the other end of which is pivotally connected at II9 with a leverI20. The lever I is secured to a rod IZI journalled in suitable bearingsI22 carried by the frame, and carries a lever I23 which actuates a boltI24 slidably mounted in a guideway I25 carried by the frame I0. As thecam IIG rotates, a spring I25 interconnected between the bolt and theguideway I25 brings a V-shaped nose I21 of the bolt into lockingengagement with one of a plurality of notches I28 in a disc I29 which issecured as by a pin I30 to the lower end of the type wheel shaft I0.Following the making of the impression, hereinafter to be described,continued rotation of the cam II6 actuates the bolt I24 moving itagainst the action of the spring I26 and disengaging it from the discI29.

Continued movement of the cam shaft I04, following the locking of thetype wheel [4, causes the carriage II, together with the work sheetcarried thereby, to move bodily against the type wheel I4, thus makingan impression on the work sheet through a ribbon I carried by a ribbonspool I35 and drawn past the printing position by a pair of coactingrolls I37 and I38. A suitable mechanism for this purpose is described indetail in my copending application Serial No. 685,107 heretoforementioned.

The carriage I I is moved toward the type wheel I4 consequent upon therotation of a cam disc I40. This cam disc is secured to the right handend of the shaft I04 and is provided with a cam groove I4I arranged tobe engaged by a roller I42 carried by a composite link, generallyindicated in Figs. 2 and 5 at I43. This link is connected, as at I39,with a lever I44 which is secured to the shaft or rod 5'! heretoforedescribed as extending between the upstanding frame brackets to the rearof the paper carriage II.

Interconnected between the rod 51 and the other paper carriagesupporting rod 58 are a plurality of toggles I46. Each toggle, Fig. 6,comprises an arm I4'I which is pinned as by a pin I49 to the rod 51, anda second arm I49 pivotally connected to the first link by a pivot pinI50, and to the rod 53 as by a pin I5I. As shown in Figs. 1, 2 and 3,there are three such toggles, one at each end of the rods 51 and 58adjacent the frame brackets 55, and one in substantially thelongitudinal center of such rods, the latter toggle being substantiallyin alignment with the axis of the type wheel I4. The axis of the rod 5!being permanently fixed relative to the frame members 55, a clockwisemovement (Fig. 6) of the rod 51 causesthe toggles to straighten, forcingthe rod 53' and accordingly the carriage II toward the type wheel I4 tocause an impression to be made. r The arrangement issuch thattheimpressionmay collar I54 to the bar 56.

9 be made by a relatively sharp blow without danger of springing thevarious parts of the carriage or the frame. To accomplish this the forceof the blow is transmitted to the framebrackets 55 through thereenforcing bar 56. As heretofore mentioned, one of the toggles is inalignment with the axis of the printing wheel I4. The frame, bar 56,opposite the point of the impression, is provided with a pin I52 havingan enlargedhead I53 which engages a collar I54 on the bar 51.

The force of the blow is therefore transmitted through this pin and thecentral toggle and the If desired the rod 58 may be provided with aroller I55 (Fig. 2) which engages the platen roller 40, thus increasingthe rigidity of the structure.

. A feature of the present invention is the provision of an improvedmechanism for controlling the forward limit of travel of the papercarriage and platen mechanism, thus controlling the printing pressure.In the present invention this is accomplished by lengthening ordecreasing the length of the composite link I43. This controls theforward limit of travel of the platen mechanism. I2 without altering itsprinting stroke. The mechanism for accomplishing this is best shown inFigs. 1,3, 14, and 16. As there shown, the roller I42 of the compositelink I43 is mounted on. an eccentric end I56 of a pin I51 which isjournalled in a sleeve I59 secured to the link. The pin is retained inthe sleeve by a setscrew I59 carried by the sleeve and engaging anannular recess formed in the pin.

The position of the eccentric portion I56 of the pin I51 is determinedby the position of an arm I60, secured to the pin, relative to a discIOI which is secured to the composite link. As shown in Figs. 14 and 15,the disc I6I is secured to the outer end of the sleeve and the arm I60is secured to the squared outer end I52 of the pin by a set screw I63 soas to overlie the disc.. The disc I5I is provided with a series ofspaced openings I64 which may be selectively engaged by a plunger I65slidably mounted in a sleeve I66 carried by the arm I60 and normallyretained inengagernent with one of the openings I54 by a spring I61. Asuitable knob I68 on the outer end of. the plunger I65 permitswithdrawal thereof and repositioning of the relative positions betweenthe arm I60 and its indexing disc I6I as desired by the operator.

Another feature of the present invention is the provision of mechanismfor controlling the movement of the platen mechanism to determinewhether or not an impression is to be effected during predeterminedcycles of operation of the machine. Such a mechanism is advantageous inthat it permits the machine to skip the actual impression operationwhenever a space key is struck without requiring the use of quads orblank spaces in the type wheel I4 and without otherwise interfering withthe normal operation of the 'machine. By eliminating theneed for quad'sor blank spaces on the type wheel I4, the wheel :inay-be provided with amaximum number of latter spaces while maintaining a minimum diameter,thus facilitating the use of a minimum size wheel, and if desiredeliminating the stopping of the rotation of the printing wheel duringspacing operations. However, I prefer to stop such rotation and bringthe printing wheel to rest with the. meeting line between two adjacenttype or characters directly opposite printing position during spacingoperations.

The control. of the movement-.ofthe platen 10.. mechanism isaccomplished by automatically decreasing the effective length of thecomposite link I43 which, as heretofore described, is part of themechanism which moves the carriage II toward the type wheel I4 to eifectthe printing operation.

The key levers 92 of the space keys 25 and the lever 95 of the space bar29 are each provided with an enlarged opening I10. These openings arenormallyaligned with each other and are arranged to receive a rod I1Iwhich is secured to a lever I12 pivoted to the frame I0 as at I13 (Fig.5).

When any one of the keys 23 or 25 is struck, the spring 04 in rockinthat respective lever 92 counterclockwise (Fig. 7) to position the typewheel I4 and release the clutch I02 to cause the shaft I 04 to make onerevolution, also causes such lever 92 to engage the rod HI and rock thelever I12 counterclockwise, around its pivot I13, against the action ofa spring I14. Such levers 92 and I12 remain in their swung position tillthe latter part of the cycle of operation. This results from the releaseof the latching connection 90, 9| between such lever 92 and itsassociated key lever 85 which frees the lever 92.

The counterclockwise movement of the lever I12 energizes a solenoid I15.As the lever I12 swings counterclockwise it closes the contacts of aleaf spring switch I19 which, as shown in Figs. 7 and 8, is mountedon astationary frame member indicated at I11. The closing of these C011.tacts energizes the solenoid I 15 and causes its armature I10 to bedrawn upward (Fig. '5). The armature I18 is pivotally connected as atI19 with a plate I which is pivoted as at I8I to the frame I0. Thus whenthe solenoid is energized the plate I80 will be rocked counterclockwise(Fig. 5) about its pivot I8I against the action of a spring I82 which isinterconnected between the plate and the frame I0. The movement of thisplate is limited by a pin and slot connection I83 with the frame.counterclockwise movement of the plate I 80 swings its hooked upper endI84 into the path of a pin I85 carried by-the composite link I43. I

When the composite link I43 is moved by the cam I40, to rock the shaft51 counterclockwise as viewed in Fig. 5 causing the paper carriage II tomove toward the type wheel to make an impression on the work sheet, theengagement of the pin I85 by the hook I84 of the plate I80 shortens thecomposite lever. This decreases the distance the paper carriage travelsto such an extent that no imprint will-be made on the work sheet.

The composite link I43 comprises two aligned bar sections I and I9I andis best illustrated in Figs. 5, 11, 12 and 13. The outer end of thesection I00 carries the cam engaging roller I42 and the outer end of thesection I9I is pivotally connected to the arm I44 which rocks the rod51. The inner end of the, section I90 is secured, as by rivets I92, to aguide I 93 in which the inner end of the section I9I is slidablymounted.

A cam plate I 94 is pivotally mounted on a stud I95 secured to thesection I90. This cam. plate is provided with a cam groove I96which'cooperates witha roller I91 mounted on a pin I98 carried by thesection I 9|. A spring I99 is connected between a pin 200, carried bythe guide I93, and the pin I85, which is carried by the cam plate I94.This spring acts to retain the cam plate in its clockwise position (Fig.11). In this position the sections I90 and I9I are separated theirmaximum distance and the composite link 11 has its maximum length. Anadjustable eccentric pin 282 is secured to the guide I93 and serves as astop for the cam plate I95, thus permitting a fine adjustment of themaximum length of the composite link I43.

When, during the movement of the link M3 toward the left in Fig. 11, theplate I83 swings upward into the path of the pin IE5, the cam plate itsis rocked about its pivot I93 from the position shown in Fig. 11, to theposition shown in Fig. 12. Such movement of the cam plate draws the linksection I95 toward the link section I90, thereby shortening the overalllength of the composite link. As this occurs during the movement of thelink the travel of the arm I i-l is decreased. This decreases the travelof the carriage I I toward the type wheel is by a distance sufficient toprevent the making of an impression on a work sheet.

On the return movement of the link I43, the pin I85 disengages the plate133 and the springs I99 and I82 return the parts to their normaloperating positions.

The rotation of the cam shaft I34 automatically restores the key leversand their associated mechanisms to their normal positions. The latchingengagement between the key lever 85 and its respective lever 92 isrestored. As shown in Fig. 8, the central portion of the shaft I84 is inthe form of an elongated cam 205 which, after the impression has beenmade, engages the lever 92 which was swung clockwise by its spring 34following the depression of the corresponding key, moving the leveragainst the action of its spring 94 to the position shown in Fig. '7.lever 32 returns to its normal position a cam portion 286 on the righthand end of the lever engages the pin. 93 of its respective key leverand rocks such lever a distance sufiicient to perma its spring 88 tocause the pin to reengage the notch 9! in the lever 92, thus latchingthe levers together.

The rotation of the shaft I34 also progresses the paper carriage I I andthe inking ribbon I35, the movement of both being under control of aratchet mechanism shown in Figs. 2, 6 and 10. Such mechanism forms thesubject of my copending application Serial No. 751,303, filed May 29. 1947. Briefly, this ratchet mechanism causes the paper carriage 11, aswell as the ribbon 135, to be advanced a distance commensurate with thewidth of the type from which the last impression :was made.

The distance the paper carriage I I is advanced is under direct controlof a pair of notched discs .216 (Fig. 6). These discs 213 are drivinglysecured to a common hub ZII which is mounted on. the lower end of thetype wheel shaft I0. Each of these discs 2H] contains a number oferipherally spaced notches 253, the position and depth of which varyaccording to the position and width of corresponding type in the typewheel I v4. As the shaft 18 is rotated to bring a specific typecharacter into printing position, the notch 2I3 corresponding to suchcharacter is brought into alignment with a spur 2I5 carried by a plrmger2I6 (Fig. 10) mounted for reciprocation in frame brackets 2I'I. Thisplunger is normally held in a retracted position against an adjustable:stop 2M by a spring 2l8 interconnected between a pin 2l9 carried by theplunger and a pin 223 .carried by a relatively stationary member.

The rotation of the shaft I during the making of the impression releasesa mechanism which causes the plunger 2H5 to be urged forward yield- Asthe r an inch from the edge of the sheet.

ingly until the end 2I5 thereof seats in the notch 2E3 of the disc 2H)which at that time is aligned therewith. As shown in Fig. 10, a cam 230is pinned to the shaft I34. While the impression is being made the shaftI24 moves a low portion of this cam into contact with a roller 23lcarried by a link 232, whereupon a spring 233 draws the link to the left(Fig. 10)

As the link 232 moves to the left, under impulse of the spring 233, theend of a slot 229 in the link 232 engages a pin 23? carried by a pawlcarrier 238 which is pivotally mounted on a shaft 239 journalled insuitable bearings 220 (Figs, 2 and 3) carried by the frame It and swingsthe carrier in a clockwise direction. The pawl carrier 238 is connectedby an elongated segment 2 (Figs. 2 and 10), with a segmental gear 243journalled on the shaft 239, and the teeth of which engage a rack-likeformation 24 3 on the left hand end of the plunger 2I6. It is thusobvious that the depth of the notch controls the amount of movement ofthe plunger 2I6 and the pawl carrier 238.

The pawl carrier 238 advances a ratchet wheel 22I which is drivinglysecured to the shaft 239. A pawl 222 carried by a lever 223 pivotallymounted on the pawl carrier 238 advances the ratchet wheel 225, adistance commensurate with the depth of the notch 2I3 which is engagedby the plunger 2I6, consequent upon the completion of a cycle ofrotation of the cam shaft I0 1. Suitable detent pawls 248 and 249 (Fig.10) prevent both overthrown and return movements of the ratchet wheel.Such pawls and their operating mechanisms are described in detail in mycopcnding application Serial No. 751,303, filed May 29, 1947.

The arcuate movement of the shaft 239 is transmitted to the carriage I Ito advance it a distance equivalent to the width of the type characterlast impressed. As shown in Figs. 2 and 10, a beveled gear 224 isdrivingly secured to the shaft 239 and meshes with a beveled gear 225drivingly secured to a shaft 226. This shaft is journalled in bearings221 carried by the frame I I]. Drivingly secured to this shaft, at therear of the machine, is a pinion 235 (Fig. 4) which meshes with a rack23B carried by the paper carriage II. Thus, the movement of the shaft239 advances or progresses the paper carriage toward the right (Fig. 4),against the action of a coil spring 245 mounted in a housing 246 carriedby the frame II] and connected with the rack 236 as at 241.

The release key 21, as heretofore mentioned. returns the carriage II toits starting position. As shown in Fig. 10, the release key 21 ismounted on a key lever 259 fixed to a shaft 25I journalled in the frameIII. This shaft carries a bar 252 which normally lies in the positionshown in Fig. 10. When, however, the key 21 is depressed, the bar 252moves counterclockwise and engages pins 253 carried by the ratchet pawls222, 248 and 249 heretofore described, moving these pawls away from theratchet wheel 22I, whereupon the spring 245 returns the carriage to itsoriginal position (to the left in Fig. 4,, or the right in Figs. 1, 2and 3).. This movement of the carriage through the gearing 235, and theshafts 226 and 239, restores the ratchet wheel 22I to its startingposition.

The paper carriage is so arranged that normally the printing of a lineis commenced a half However, it is sometimes desirable to commence theprinting .line .a greater distance from the edge of the margin, the rack236 is adjustably mounted on the carriage H.

As indicated in Figs. 4, 6 and 17, the rack is mounted for longitudinalmovement between a pair of downwardly extending ears 260 formed in eachcarriage end plate 30 and 3|. The rearmost ear of each pair has a tonguewhich engages a longitudinally extending groove 26I in the rack bar 236and maintains the vertical relationship between the rack and carriage.

The rack bar is normally latched to the carriage. As shown in Figs. 6and 17, a latch bar 262 is pivoted on a pin 263 carried by a bracket 264which is secured to the rack bar 236 by studs 265. A spring 266,interposed between the latch bar and the bracket, normally maintainsteeth 26'! formed on the latch bar in engagement with the teeth of arack-like formation 268 on the underside of the carriage frame bar 34,thereby latching the rack 236 to the carriage.

An indicator is provided to visibly indicate'the position of the rackbar 236 relative to the carriage II. The latch bracket 236 is providedwith an upstanding pin 210 having an index mark 2' on its upper end.This index mark coacts with a scale 212 (Fig. 18) inscribed on the uppersurface of the carriage frame bar 33.

When it is desired to adjust the left-hand margin of the imprint on thework sheet, to say three inches, the operator depresses a key 215 whichreleases the latch and locks the rack bar 236 in a definite positionrelative to the frame ID. Following the depression of the key theoperator moves the carriage until the index 2' is opposite the threeinch mark on the scale 212. The key is then released whereupon the latchreturns to its normal position and latches the rack bar 236 to thecarriage.

The key 215 (Figs. 1, 5 and 17) is mounted on the upper end of a rod 216which is slidably mounted in the reenforcing bar 36 at the rear of themachine. A spring 211 normally retains the key 215 in its uppermostposition. When the key 21-5 is depressed, the lower end of the rod 216engages the outer end of the latch bar 262 rocking it from the positionshown in Fig. 6 to the position shown in Fig. 17. This movement of thelatch bar disengages the teeth 261 thereof from the rack 268 of the bar34, thereby releasing the rack 236 to permit relative movement betweenthe rack 236 and carriage.

Prior to the completion of the release of the rack 236 by the latch bar262, this bar engages a slot 218 formed in the upper end of a post 219which is secured to the frame ID as by studs 280. This latches the rack236 to the frame H] and facilitates the movement of the carriage by theoperator.

I claim:

1. In a printing machine of the keyboard type, a frame, a type wheelrotatably mounted on said frame, a plurality of keys, a plurality oftype extending about the periphery of said wheel, key controlled meansto bring a selected type into printing position, a pair of parallel rodscarried by said frame, one of said rods having its axis fixed relative'to said frame, the other of said rods having its axis movable relativeto the frame,

a. carriage slidably mounted on said last named rod, means on saidcarriage to support work, an elongated platen bar fixed to said carriageand extending parallel t and in the same plane as said rods, togglemeans interconnecting said rods to move the axis of the last named rodand the 14 carriage toward and from the type wheel to cause animpression to be made on the work, key controlled means to rock thefirst named rod to actuate said toggle means, a guide bar secured tosaid'carriage and extending parallel with said' rods but spacedtherefrom, and a pairof rollers mounted on said frame and embracingsaidbar to prevent rocking of the carriage about its supporting rod. i

2. In a printing machine of the keyboard type. a frame, two groups ofkeys thereon, a carrier having a plurality of type faces thereon, means:

; movement whenever the keys of such group are actuated.

3. In a printing machine of the keyboard-type, a frame, a'plurality ofkeys thereon, a carrier having a plurality of type faces thereommeansincluding certain of said keys to bring a selected type face intoprinting position, a work carrier,"

one of said carriers being mounted for movement to and from the othercarrier to efifect'anirm pression on work, mechanism to move said movable carrier including an adjustable member to vary the amount of suchmovement, means under control of said keys to actuate said mechanism,and means under control of certain of said keys' and coacting with saidadjustable member to vary the amount of said movement.

4. In a printing machine of the keyboard type, a frame, a plurality ofkeys thereon, a" carrier having a plurality of type faces thereon sideby side, means including one group of said keys to bring a selected typeface into printing position,

means including another group of keys to posi-' tion said carrier with apoint intermediate two type faces in printing position, a work carrier,one of said carriers being mounted for movement to andfrom the othercarrier to effect an impresnamed means to control the amount of saidmovement, and means under control of the keys of both groups to actuatesaid mechanism.

5. In a printing machine of the keyboard type,

a frame, a plurality of keys thereon, a carrier' having a plurality oftype faces thereon, means including certain of said keys to bring aselected type face into printing position, a work carrier, one of saidcarriers being mounted for movement to and from the other carrier toeffect an impression on work, mechanism to move said movable. carrierincluding a composite link to controlthe amount of such movement, saidlink comprising a pair of members movable relative to each other tocontrol the length of said link, means 'under control of said keys toactuate said mechanism, and means under control of certain of said keysand coacting with said composite link to move one of its members towardits other member to decrease the length of said link. i

6. In a printing machine of the keyboard type,

M a-ass airtime a p ra i y Q k ys i l teqn sa -1 avin a. lura it f ypeac there n, m ns n udin er a n o a d eys to ne a s ec e t pe ia in o prit n P9$ a rk r; 91 2 f s d rrie bei m u ted or m m t 9 and fro h o ercarr er 9 efisc imrressisn on work, mech nism t me e said a m -ble carrer. ope ating ean for sa dmeshe nism, an adjustable link pivoted at oneend to said meehaa m nd at its o her and to a Operati mean to tra s t te m ement i Said m an t s id m c s said link nc d 1 ai mb rs mo b e reati is e. To ether o de re s t e ef e e l ng h i a ,1 1 res ent mea s isrm l y eta sa em ers separate cam an to mo e a d m mbe oa d ach th eansn e c n r o s id keys to actuate said mechanism, and means un- 1 on l fcer ain of a keys d mee in ith Sa d c m m a to crea h en th o said v 11a. P g i e 9 h keyboa d ypo a plurality of keys, a movably mounted typecar.- rier having a plurality of type, means controlled by certain ofsaid keys to position a selected type on said carrier in printingposition, a mov- 31 mo ed, W k lmlde means 9 u e relative movementbetween the work holder and the t pe c rrie to use an p eseiq to be mfrom s e t and in lu ing a su nt longitudinally movable link, means to.move said link a predetermined distance to cause an impression to bemade, said link comprising a pair of longitudinally extending membersmovable relative to each other, cam means to move said members towardeach other, resilient means acting on said cam means to move saidmembers away from each other, an adjustable member to limit the movementof said members away from each other, and means actuated by certain of isaid keys and projectable into the path of said cam means to counteractsaid resilient means consequent upon movement of said link.

.8. In a printing machine of the keyboard type, a plurality of keys, amovably mounted type carrier having a plurality of type, means comtrolled by certain of said keys to position selected type on saidcarrier in printing 110E517 .tion, a movably mounted work holder, meansto cause relative movement between the work hold-- er and the typecarrier to cause an impression to be made from a selected type andincluding an adjustable member to control the amount of such movement,an operating member having an adjustableconnection with said inemoer,manually settable means to control said adjustable connection, meansactuated by oe tain of said keys and operative on said adjustable memberto vary the amount of such movement whenever one of the last mentionedI; h actuated, and means to restore said adjustable member followingeach cycle of operation of said machine. 7

9. In a printing machine of the keyboard type, a frame, a plurality ofkeys, a movably mounted type carrier having a plurality of type, incontrolled by certain of said keys to position a selected type on saidcarrier in printingposh tion, a movably mounted work holder, a toggleconnected to move the work holder relative to the type carrier to causean impression to be made from a selected type, a rock arm to actuatesaid toggle, a cam, a link having one end pivotall connected to saidrock arm, vroller on the other end of said link and engaging saideam,-said link comprising a pair of telescopically mounted members, acam pivoted to one of said members and provided with a cam groove, a inor mounted on the other member and coacting with said groove, resilientmeans acting on said cam to cause said cam to move said telescopingmembers away from each other, a pin on said earn, an arm mounted on saidframe and swingable into the path of said pin, a solenoid emtive y wn qis a iseie said arm, n an electric switch actuatable by certain of saidkeys to energize said solenoid.

10. In a printing machine of the keyboard e, trams, a plurality of keys,a movably lllounted type carrier having a plurality of typ faces, meanscontrolled by certain of said 1: to position a selected type face onsaid car in printing position, a movably mounted w holder, a toggleconnected to move the work hols or relative to the type carrier to causean "lpression to be made from a selected type a reek arm to actuate saidtoggle, a cam, a link having one end pivotally connected to said rockarm, a roller on the other end of said link and engaging said cam, aneccentric connection between said roller and link to vary the effectivelength of said link, manually settable means to control the position ofsaid eccentric connection, said link comprising a pair of telescopicallymounted members, a cam pivoted to one of said members and provided witha cam groove, a re er mounted on the other member and coacting v, saidgroove, resilient means acting on said com to move said telescopingmembers from each other, adjustable means to limit said last mentionedmovement, a pin on said cam, an arm mounted on said frame and swingableinto the path of said pin,-a solenoid operatively connected to actuatesaid arm, an electric switch actuatablc by certain of said keys toenergize said solenoid, and means to release said arm consequent uponthe completion of a cycle of operation.

i l. In a printing machine of the keyboard type, a frame, a plurality ofmanuall operable keys mounted thereon, a type carrier movably mounted onsaid frame and provided with plurality of type, means including certainof said keys to control the movement of said type carrier to bring aselected type into printing position, a work holding carriage mounted onsaid frame for bodily movement toward and from said type carrier toeiiect an impression on work, a toggle to move said carriage, a rock armto actuate said toggle, a link pivoted at one end to said arm, meanspivotally connected to the other end of said link to actuate said link,said last named means being under control of said keys, manuallysettable means to adjust the length of said link to control the forwardposition of said carriage relative to said type carrier, and meansacting automatically consequent upon the operation of certain of saidkeys to further change the length of said link.

12. In a printing machine of the keyboard type, a frame, a plurality ofkeys mounted there- I? a latch to latch said rack in an adjustedposition relative to said carriage, and means to latch said rack againstmovement relative to said frame.

13. In a printing machine of the keyboard type, a frame, a plurality ofkeys thereon, a carrier having a plurality of type faces thereon, meansincluding said keys to bring a selected type face into printingposition, a work carrier, one of said carriers being mounted formovement to and from the other carrier to effect an impression on work,means under control of said keys to effect letter spacing of said workcarrier, said means including a gear mounted on said frame, a rackmovably mounted on said work carrier and coacting with said gear, alatch to latch said rack to said work carrier, means to release saidlatch, and means actuated by said last named means to latch said rack tosaid frame prior to its release.

14. In a printing machine of the keyboard type, a frame, a plurality ofkeys movably mounted thereon, a type carrier having a plurality of typemovably mounted on said frame, means controlled by said keys to positionsaid carrier with a selected type in printing position, a work holdermovably mounted on said frame, means controlled by said keys to causerelative movement between the work holder and the type carrier to causean impression to be made from a selected type, means controlled by saidkeys to move said work holder step by step relative to said frame toeffect letter spacing of said work, said last named means including arack slidably mounted on said holder and a gear carried by said frameand drivingly coacting therewith, a second rack secured to said holder,a stop secured to said frame, a latch arm mounted on the first namedrack and movable into engagement with said second named rack to latchsaid holder thereto and movable into engagement with said stop to latchsaid first named rack to said frame, said latch arm being at all timesin engagement with either said stop or said second named rack, andmanually operable means to control the position of said arm.

15. In a printing machine of the keyboard type, a frame, a type wheelrotatably mounted on said frame, a plurality of keys, a plurality oftype extending about the periphery of said wheel, key controlled meansto bring a selected type into printing position, a pair of parallel rodscarried by said frame with their axes in a substantially horizontalplane extending through the printing position, one of said rods havingits axis fixed relative to said frame, the other of said rods having itsaxis movable relative to said frame in said horizontal plane, a carriageslidably mounted on said last named rod for movement axially thereof,means on said carriage to support work, an elongated platen mounted onsaid carriage and extending parallel with and in the same plane as saidrods, toggle means interconnecting said rods to move the axis of thelast named rod horizontally to move the carriage toward and from thetype wheel to cause an impression to be made on the work, key controlledmeans to actuate said toggle means, a guide bar fixed to said carriageand extending parallel with said rods but spaced below said plane, meansmounted on said frame and engaging said bar t prevent upward movement ofsaid carriage, and means mounted on said frame and engaging said bar toprevent downward movement of said carriage, thereby preventing rockingof the carriage about its supporting rod.

16. In a printing machine of the keyboard type, a frame, a type wheelrotatably mounted on said frame, a plurality of keys, a plurality oftype extending about the periphery of said wheel, key controlled meansto bring a selected type into printing position, a work holdingcarriage, a pair of parallel rods carried by said frame, one of saidrods having its axis fixed relative to said frame and movable relativeto said carriage, the other of said rods having it axis movable relativeto the frame and fixed relative to the carriage, said carriage beingslidably mounted on said last named rod for axial movement relativethereto, means on said carriage to support work, an elongated platen barfixed to said carriage and extending parallel to and in the same planeas said rods, toggle means interconnecting said rods to move the axis ofthe last named rod and the carriage toward and from the type Wheel tocause an impression to be made on the work, key controlled means toactuate said toggle means, a guide bar secured to said carriage andhaving a pair of oppositely facing surfaces extending parallel with saidrods but spaced from said plane, and means mounted on said frame andengaging said bar surfaces to prevent rocking of the carriage about itssupporting rod, said bar being freely movable relative to said means ina plane parallel with said first named plane to permit movement of thecarriage to and from said type wheel and axially relative to said rods.

17. In a printing machine of the keyboard type, a frame, a type wheelrotatably mounted on said frame, a plurality of keys, a plurality oftype extending about the periphery of said wheel, key controlled meansto bring a selected type into printing position, a pair of parallel rodscarried by said frame, one of said rods having its axis fixed relativeto said frame, the other of said rods having its axis movable relativeto the frame, a carriage slidably mounted on said last named rod, meanson said carriage to support work, an elongated platen bar fixed to saidcarriage and extending parallel to and in the same plane as said rods,toggle means interconnecting said rods to move the axis of the lastnamed rod and the carriage toward and from the type Wheel to cause animpression to be made on the work, key controlled means to actuate saidtoggle means, a guide bar secured to said carriage and extendingparallel with said rods but spaced therefrom, said bar having oppositelyfacing surfaces parallel with said lane, and a pair of spaced rollersmounted on said frame and engaging respective surfaces of said bar toprevent rocking of the carriage about its supporting rod, said bar beingslidable relative to said rollers in a direction parallel with saidplane, and said rollers being mounted with their axes in a planeparallel with the axis of said type wheel and passing through theprinting position.

CLIFTON CHISHOLM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 481,376 Spiro Aug. 23, 1892499,498 Barten June 13, 1893 811,247 Roussel Jan. 30, 1906 2,506,701Chisholm May 9, 1950

